The present invention relates to an optical disk drive using an optical disk as a recording medium.
An optical disk drive adopts an optical disk such as a compact disk (CD), a VIDEO-CD, a laser disk (LD), a digital video disk (DVD), a CD-ROM or a DVD-ROM as a recording medium..
Generally, an optical disk drive should be capable of storing much information in a disk and be installed stably regardless of the installation direction and position. Also, assembling and maintenance thereof should be simple and convenient.
The above requirements of the optical disk drive will be described with reference to FIGS. 1, 2A and 2B.
First, in order to store a large amount of information in a disk 1, information should be recorded on the disk 1 with high density. That is, the width of the tracks on the disk 1 and the interval between the tracks should be narrow. As described above, in order to store information in the disk 1 with high density or reproduce the stored information with high density, a highly precise optical pickup 2 and a deck mechanism 3 are also required.
For realizing the highly precise deck mechanism 3, an optical axis of light beam radiated from the optical pickup 2 to the disk 1 should be precisely movable radially with respect to the disk. For the above, the phase and the tilt of the optical pickup 2 should be precisely adjusted.
A phase difference occurs when the beam radiated from the optical pickup 2 deviates from the radial optical path on the disk 1 seated on a turntable 4. Also, the tilt occurs when the optical axis of the beam is tilted with respect to the disk 1. The tilt is divided into two components, that is, a radial tilt in which the beam is tilted to the radius direction of the disk 1, and a tangential tilt in which the beam is tilted to the tangential direction of the disk 1. The tilt is caused by assembling errors of shafts 5 for guiding the optical pickup 2 in the radial direction of the turntable 4 or from an assembling error of a spindle motor 7 installed on a deck 6. That is, the tilt occurs when the shafts 5 are not installed horizontally with respect to the deck 6, or when the spindle motor 7 is not installed vertically with respect to the deck 6 so that a rotary shaft 8 of the spindle motor 7 is not vertical with respect to the deck 6.
Second, each constituent such as tray 9, deck 6, optical pickup 2 and ascending/descending means (not shown) should be designed and assembled stably regardless of the installation direction and location. For example, as shown in FIG. 2A, there is no problem when an optical disk drive 10 is installed in the horizontal direction. However, as shown in FIG. 2B, a problem may occur when the optical disk drive 10 is installed in the vertical direction.
Third, each constituent to be assembled on a base frame (not shown) such as tray 9, deck 6, optical pickup 2 and ascending/descending means (not shown) should be properly designed for easy and simple assembling of the optical disk drive 10.
Fourth, constituents which are malfunctioning should be easily replaceable for easy and convenient maintenance. For example, if the phase and the tilt of the optical axis of the beam radiated from the optical pickup 2 to the disk 1 are changed when replacing a malfunctioning optical pickup 2, the phase and the tilt normally must be readjusted.